Packet-based communication systems allow the user of a device, such as a personal computer, to communicate across a computer network such as the Internet, in which case the packet protocol may be Internet Protocol (IP). Packet-based communication systems can be used for video communications. These systems are beneficial to the user as they are often of significantly lower cost than fixed line or mobile networks. This may particularly be the case for long-distance communication. To use a packet-based system, the user must install and execute client software on their device. Such client software can establish voice and video calls.
In a video communication system, during a video call, a first user's terminal will receive video and speech data from a second user's terminal. The received video data typically comprises real-time video of the second user's face or body during the call. The received video data will typically be displayed in a main video area of a display on the first user's terminal. The video data is encoded by an encoder at the second user's terminal for transmission to the first user's terminal. The received video data is then decoded by a decoder at the first user's terminal.
These video communication systems allow for video conferences between a plurality of users. In such systems received video data from the plurality of users will typically be displayed in a main video area of a display on each of the user's terminals The Polycom® CX5000 is a device that can be used in collaboration to Microsoft® Office Live Meeting 2007 and Microsoft® Office Communications Server 2007. The Polycom® CX5000 device comprises a plurality of cameras to provide a panoramic view of a video conference. A user interface displays all of the participants in a panoramic display area which comprises a display area for each of the participants. When a participant of the video conference is speaking they are displayed in the panoramic display area with the other participants of the video conference, in addition to being displayed in an active speaker area of the user interface. The active display area is larger than a participants display area in the panoramic display area. Therefore the relative size of the video display for the participant who is currently speaking is changed to fit the active display area, whilst the display of the active speaker in the panoramic display area remains the same size. This enables the current speaker of the video conference to be more clearly displayed at the user terminals of the plurality of users.
In this system the active participant is determined based on an instantaneous assessment of the participant's activity in the video call and the display of the active participant is changed accordingly.